1. Field of the Invention
The present invention relates to a distribution system for use with a seed planter, and more particularly, to a seed distribution system for supplying seed to a plurality of seed metering units associated with the seed planter.
2. Description of Related Art
Distribution of seeds using a planter or seeder is typically accomplished by providing a seed metering unit for dispensing seeds from a hopper at a controlled rate into an underlying drop chute for conveying the seeds to a furrow. Examples of typical metering systems are disclosed in U.S. Pat. Nos. 3,888,387 and 4,450,979, both to Decklet, which disclose metering units for accurate metering and uniform distribution of seed. One problem associated with such metering units results from each metering unit being fed from a separate hopper or bin located above the metering unit such that each bin must be separately filled and emptied before and after a seeding operation. Thus, the servicing of individual bins for the metering units can be time consuming and inconvenient.
U.S. Pat. No. 4,296,695 to Quanbeck illustrates a seed distribution system which overcomes the problems associated with providing a plurality of seed bins for individual metering units. In this patent, a system is disclosed which provides a central seed hopper which distributes seed to a plurality of distribution tubes or hoses for supplying seed to furrow openers on a seeding apparatus. A disadvantage associated with such a distribution system is that it is not adapted to be used with a planter having individual metering units for each furrow. Thus, the seeds may become grouped together before they are dropped in the furrow, such that the spacing of the seeds within a furrow may be less uniform than if the metering apparatus were located directly adjacent to the furrow opener.
U.S. Pat. No. 5,161,473 to Landphair et al discloses a seed distribution system for overcoming some of the disadvantages associated with prior art seed distribution systems. The Landphair et al patent discloses a metering apparatus directly adjacent to each furrow opener as well as a main storage hopper to provide seed to a plurality of secondary hoppers associated with each of the metering devices. This device further includes a plurality of seed tubes for supplying seed to each secondary hopper wherein the seed tubes each include an input end located within the main hopper and an air tube which surrounds each seed tube to blow air into the main hopper whereby seeds are propelled through the seed tubes to respective secondary hoppers. Thus, each seed tube requires a separate air supply tube to force air and seed into the seed tube. Further, the amount of seed being fed through any particular seed tube will depend upon the position of the seed tube relative to the seed in the area of the tube such that the quantity of seed flowing through the seed tubes may vary from seed tube to seed tube. In such a distribution system, wherein there may be large variations in the flow of seed through the different seed tubes, it is necessary to provide secondary hoppers with a sufficient size to ensure that a sufficiently large reserve of seed is provided at each seed metering device to compensate for any interruption or unexpected decreases in the flow of seeds to any of the secondary hoppers.
It is desirable to provide a seed delivery system wherein a substantially uniform distribution of seed is provided to a plurality of secondary hoppers and wherein the size of the secondary hoppers is limited such that a minimum amount of seed is stored at each of the metering device sites. Thus, if it is necessary to remove the seed from the system, the labor and loss of seed involved in removing the seed stored in the system will be minimized.